In conventional press casting machines the tool halves, which when they are joined together form a mold, are fastened in such a way, that it is very hard and time-consuming to exchange tool halves, which also are called mold tools. On production-technical grounds press casting machines are to be used during long periods of time, which means, that a multishift-use will be the most common one. Consequently, presently used tool exchanges seldom coincide with possible downtime periods, and an exchange must then be done in the middle of a production period.
A conventional exchange, which requires an interference with the interior parts of the machine, implies first of all a certain cooling period in order to at all allow the personnel to work with the machine without substantial burn injury risks. Said cooling period may be as long as 20-60 minutes, which is a long period of time, during which a large energy consumption takes place in order to keep the metal, which is to be molded, liquid and during which the production is standing still.
Also, without direct burn injury risks machine manipulations are difficult and risky, since the available space is very small and thus, injuries easily happen and the operation position often is very inadequate from an ergonomical point of view. An exchange, which is done completely in a manual way, requires usually 2-3 hours. Since the operation is done completely in a manual way, human errors may also easily occur. By way of example bolts and nuts, which are not sufficiently tightened, may result in that a machine part comes loose and castings will be rejected and tools be destroyed.
Also, mere service work is subjected, as to conventional press casting machines, to the above-mentioned drawbacks. This may result in that regular service work is neglected and the machine and machine parts are subjected to an increased wear as well as in that the products will have an inferior quality. In case a strongly different product category is to be produced instead, the parent tools must also be exchanged, which means production reductions during a period of 6-12 hours, apart from a very demanding and expensive effort in a very exacting working environment.
Known technique is revealed by U.S. Pat. No. 4,449,907, U.S. Pat. No. 4,529,371, U.S. Pat. No. 4,758,147, DE-A-3 220 911, DE-A-3 737 598, EP-A-0 353 597 and JP 58-65 560.
U.S. Pat. No. 4,449,907 relates to a device for exchange of tools at an injection machine for plastic material incorporating horizontally active tools and a vertical parting plane. In this case, don't arise same or similar problems as mentioned hereinbefore in connection with vertically active press casting machines for metal do not arise. Neither is there any comparable design of machines.
U.S. Pat. No. 4,529,371 concerns, like the afore-mentioned publication, a device for exchange of tools at an injection machine for plastic material.
U.S. Pat. No. 4,758,147 is a further example of a device for exchange of tools at an injection machine for plastic material.
DE-A-3 220 911 is still a further example of a device for exchange of tools at an injection machine for plastic material.
DE-A-3 737 598 refers also to a horizontally active injection machine and a device for exchange and positioning of tools in connection with such machine. Even here, there are no comparable problems and solutions to such.
EP-A-0 353 597 concerns a horizontally active injection machine with vertical parting plane. Although there are vertically adjustable supporting plates for the tools as well as an elevator and a turning device, all this equipment is arranged outside the machine and without any comparability with the problems of a vertically active press casting machine.
JP 58-65 560 is the only one of these publications to concern a vertically active press casting machine, where tools may pass through the machine, but without lifting of the parent tool or any tool half. These machine parts can consequently not pass any obstacles as other machine parts, e.g. core pulling devices which extraordinarily limits design and usability of the machine. This conventional machine lacks upper injection plunger and provides supply of metal from below. Discharge takes place in the upper mould half and the tool exchange device occupies two sides of the machine. Any tool handling in connection with this machine is neither shown nor described.